When using nitrile reclaimed rubber to produce high-hardness rubber products, in addition to the choice of high-recycled reclaimed rubber and original rubber, it is also necessary to pay attention to the rubber product formulation design. In addition, due to the high hardness of the nitrile reclaimed rubber during mixing and vulcanization. It is easy to generate heat and has a bad influence on the normal production of rubber products. Therefore, it is necessary to strictly control the production process, mainly including the mastication process, the mixing process, and the vulcanization process.
1. High-hardness nitrile reclaimed rubber product plasticating and mixing process
The higher the hardness of the nitrile reclaimed rubber, the easier it is to heat the friction during the mastication and mixing process. The mastication of the nitrile rubber or the nitrile reclaimed rubber needs to be carried out in a cold roll, followed by the addition of sulfur, softener, Filling agent and other compounding agent are mixed; in the process of mixing, it needs to be cooled in time. Generally, cooling water is introduced into the roller of the rubber mixer; it should be noted that the accelerator is added last to avoid scorch.
2. High hardness nitrile reclaimed rubber product vulcanization process
Vulcanization is one of the most important processes in the production of rubber products. Many rubber products manufacturers choose high-temperature vulcanization in order to improve the vulcanization efficiency. However, since high-hardness nitrile reclaimed rubber generates a large amount of heat during the vulcanization process, high-temperature vulcanization is prohibited. Select low temperature for long-term vulcanization to avoid explosion due to excessive vulcanization rate and excessive heat generation; since the heat generated by vulcanization of nitrile reclaimed rubber is very large, rubber products manufacturers should use segmental vulcanization; in the adjustment of nitrile reclaimed rubber vulcanization At the time of speed, it is necessary to properly control the vulcanization speed. If the vulcanization rate is too fast, the vulcanizate may be too brittle, the surface may have bubbles or the surface may not be smooth.
3. High-hardness nitrile reclaimed rubber product trimming process
Trimming is the last major process in the processing of rubber products. Hard nitrile reclaimed rubber products are inherently brittle, so rubber products manufacturers need to perform trimming at a slightly higher temperature than normal temperature when trimming the model products. Damage occurs on the side; for the extruded rubber products such as nitrile rubber tube and nitrile rubber rod, the outer edge of the reclaimed rubber product can be processed by grinding.
There are many kinds of high-hardness rubber products produced by using nitrile reclaimed rubber. The shape, thickness and use are very different. Therefore, the mastication process, the kneading process, the vulcanization process and the trimming process are very different. For example: thin-wall type high-hardness nitrile reclaimed rubber products can be directly vulcanized by steam in water, in addition to high-density nitrile reclaimed rubber. The nitrile rubber sheet can be vulcanized with tin foil on both sides. Rubber products manufacturers need to rationally adjust each production process of high hardness nitrile reclaimed rubber products according to demand.